The cathedral, of the 12th century, has a carved portal and three apses decorated with small arches and pilasters, and contains a fine pulpit and episcopal throne in marble mosaic. Near it are two grottos 1 To the period after 335 belong numerous silver and bronze coins with the legend Caleno.
Amongst the best-known are the grottos of Adelsberg, the larger ones of Planina and the Kreuzberghohle near Laas.
At Syracuse also there are very extensive catacombs known as " the Grottos of St John."
He is always associated with his brother Trophonius as a wonderful architect, the constructor of underground shrines and grottos for the reception of hidden treasure.